Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 71 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 11 cm. What happens? (a) buzzer is silent (b) buzzer beeps
2. 2.⏱️ loop forever { LED ON; wait 800 ms; LED OFF; wait 700 ms }
   How many milliseconds does one blink (ON + OFF) take?
3. 3.⚠️ Why must we never touch switches with wet hands? (a) it is just untidy (b) water carries current (c) it spoils the paint (d) water makes it cold
4. 4.🧮 A 20 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
5. 5.True or false: to make a parking alarm, use a distance sensor. (a) False (b) True
6. 6.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it lights brighter (c) it does not light (d) it changes colour
7. 7.True or false: to use daylight to read wastes electricity. (a) True (b) False
8. 8.🌐 In an IoT system, which part reads values, decides? (a) Wi-Fi (b) cloud server (c) microcontroller (d) sensor
9. 9.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 5 % (d) 25 %
10. 10.⏱️ How many milliseconds is a wait of 0.3 seconds?
11. 11.🧮 A 5.5 V battery is joined to 6 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
12. 12.🔁 count = 1
    while (count < 10) { count = count + 3 }
    How many times does the loop run?
13. 13.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “switch the pump on/off”? (a) switch the pump on/off (b) compare with the limit
14. 14.True or false: to throw cells in a fire is safe. (a) True (b) False
15. 15.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) an LED lamp (d) a candle
16. 16.True or false: a thermistor makes things spin. (a) False (b) True
17. 17.🌐 Is a plain wall switch an IoT device? (a) not an IoT device (b) an IoT device
18. 18.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
19. 19.✏️ Why do engineers draw circuits with symbols? (a) symbols are heavier (b) to make it colourful (c) quick and clear for all (d) to hide the circuit
20. 20.Which of these is an input? (a) a speaker (b) a motion sensor (c) a buzzer (d) a small display
21. 21.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 680 Ω resistor? (a) blue-grey-red (b) grey-blue-brown (c) blue-grey-black (d) blue-grey-brown
22. 22.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
23. 23.🔋 Does a battery give electricity or use electricity? (a) uses electricity (b) gives electricity
24. 24.🔋 Cells joined + to − in a row (series) give … (a) a smaller voltage (b) no voltage (c) a bigger voltage (d) the same voltage
25. 25.🧭 Which part of a microcontroller board runs the program? (a) the main chip (b) the voltage regulator (c) the pins (d) the power LED
26. 26.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.True or false: “one out, the rest glow” is true of a parallel circuit. (a) True (b) False
29. 29.Which of these is an insulator? (a) a rubber band (b) a steel spoon (c) a copper wire (d) an iron nail
30. 30.True or false: energy used each second is measured in watts (W). (a) True (b) False
31. 31.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
32. 32.📏 Which unit measures the push of a cell? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
33. 33.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
34. 34.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
35. 35.Which of these usually has a microcontroller inside? (a) a TV remote (b) a candle (c) a spinning top (d) a wind-up toy
36. 36.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.🔁 count = 3
    while (count < 33) { count = count + 5 }
    How many times does the loop run?
38. 38.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
39. 39.🔁 count = 8
    repeat 6 times { count = count + 3 }
    What is count at the end?
40. 40.True or false: to build with an adult near is not safe. (a) True (b) False

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